M G Duravent 8DT-36SSCF 8 Inch x 36 Inch Dura Vent Duratech Length 430-alloy Stainless Inner Liner Stainless Outer has been filling the supply and accessory needs of over 8, 000 sweeps hearth retailers masons and contractors for over 25 years. has the privilege of serving over 80% of the professionals in America.Founded by Robert Daniels Sooty Bob in 1978 has grown from a one-man operation to a national network of six warehouses and a manufacturing plant. From its headquarters in Fairfield Iowa plays a major role in providing for the industry. 430-alloy Stainless Inner Liner, Stainless Outer.